776223a6fc
Based on https://www.redhat.com/archives/dm-devel/2019-March/msg00025.html Third version of dm-bow. Key changes: Free list added Support for block sizes other than 4k Handles writes during trim phase, and overlapping trims Integer overflow error Support trims even if underlying device doesn't Numerous small bug fixes bow == backup on write USE CASE: dm-bow takes a snapshot of an existing file system before mounting. The user may, before removing the device, commit the snapshot. Alternatively the user may remove the device and then run a command line utility to restore the device to its original state. dm-bow does not require an external device dm-bow efficiently uses all the available free space on the file system. IMPLEMENTATION: dm-bow can be in one of three states. In state one, the free blocks on the device are identified by issuing an FSTRIM to the filesystem. In state two, any writes cause the overwritten data to be backup up to the available free space. While in this state, the device can be restored by unmounting the filesystem, removing the dm-bow device and running a usermode tool over the underlying device. In state three, the changes are committed, dm-bow is in pass-through mode and the drive can no longer be restored. It is planned to use this driver to enable restoration of a failed update attempt on Android devices using ext4. Test: Can boot Android with userdata mounted on this device. Can commit userdata after SUW has run. Can then reboot, make changes and roll back. Known issues: Mutex is held around entire flush operation, including lengthy I/O. Plan is to convert to state machine with pending queues. Interaction with block encryption is unknown, especially with respect to sector 0. Bug: 119769411 Change-Id: Id70988bbd797ebe3e76fc175094388b423c8da8c Signed-off-by: Paul Lawrence <paullawrence@google.com>
566 lines
19 KiB
Plaintext
566 lines
19 KiB
Plaintext
#
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# Block device driver configuration
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#
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menuconfig MD
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bool "Multiple devices driver support (RAID and LVM)"
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depends on BLOCK
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select SRCU
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help
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Support multiple physical spindles through a single logical device.
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Required for RAID and logical volume management.
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if MD
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config BLK_DEV_MD
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tristate "RAID support"
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---help---
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This driver lets you combine several hard disk partitions into one
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logical block device. This can be used to simply append one
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partition to another one or to combine several redundant hard disks
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into a RAID1/4/5 device so as to provide protection against hard
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disk failures. This is called "Software RAID" since the combining of
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the partitions is done by the kernel. "Hardware RAID" means that the
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combining is done by a dedicated controller; if you have such a
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controller, you do not need to say Y here.
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More information about Software RAID on Linux is contained in the
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Software RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also learn
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where to get the supporting user space utilities raidtools.
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If unsure, say N.
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config MD_AUTODETECT
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bool "Autodetect RAID arrays during kernel boot"
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depends on BLK_DEV_MD=y
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default y
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---help---
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If you say Y here, then the kernel will try to autodetect raid
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arrays as part of its boot process.
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If you don't use raid and say Y, this autodetection can cause
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a several-second delay in the boot time due to various
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synchronisation steps that are part of this step.
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If unsure, say Y.
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config MD_LINEAR
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tristate "Linear (append) mode"
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depends on BLK_DEV_MD
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---help---
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If you say Y here, then your multiple devices driver will be able to
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use the so-called linear mode, i.e. it will combine the hard disk
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partitions by simply appending one to the other.
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To compile this as a module, choose M here: the module
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will be called linear.
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If unsure, say Y.
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config MD_RAID0
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tristate "RAID-0 (striping) mode"
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depends on BLK_DEV_MD
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---help---
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If you say Y here, then your multiple devices driver will be able to
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use the so-called raid0 mode, i.e. it will combine the hard disk
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partitions into one logical device in such a fashion as to fill them
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up evenly, one chunk here and one chunk there. This will increase
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the throughput rate if the partitions reside on distinct disks.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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To compile this as a module, choose M here: the module
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will be called raid0.
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If unsure, say Y.
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config MD_RAID1
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tristate "RAID-1 (mirroring) mode"
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depends on BLK_DEV_MD
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---help---
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A RAID-1 set consists of several disk drives which are exact copies
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of each other. In the event of a mirror failure, the RAID driver
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will continue to use the operational mirrors in the set, providing
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an error free MD (multiple device) to the higher levels of the
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kernel. In a set with N drives, the available space is the capacity
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of a single drive, and the set protects against a failure of (N - 1)
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drives.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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If you want to use such a RAID-1 set, say Y. To compile this code
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as a module, choose M here: the module will be called raid1.
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If unsure, say Y.
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config MD_RAID10
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tristate "RAID-10 (mirrored striping) mode"
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depends on BLK_DEV_MD
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---help---
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RAID-10 provides a combination of striping (RAID-0) and
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mirroring (RAID-1) with easier configuration and more flexible
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layout.
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Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
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be the same size (or at least, only as much as the smallest device
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will be used).
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RAID-10 provides a variety of layouts that provide different levels
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of redundancy and performance.
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RAID-10 requires mdadm-1.7.0 or later, available at:
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ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
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If unsure, say Y.
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config MD_RAID456
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tristate "RAID-4/RAID-5/RAID-6 mode"
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depends on BLK_DEV_MD
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select RAID6_PQ
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select LIBCRC32C
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select ASYNC_MEMCPY
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select ASYNC_XOR
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select ASYNC_PQ
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select ASYNC_RAID6_RECOV
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---help---
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A RAID-5 set of N drives with a capacity of C MB per drive provides
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the capacity of C * (N - 1) MB, and protects against a failure
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of a single drive. For a given sector (row) number, (N - 1) drives
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contain data sectors, and one drive contains the parity protection.
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For a RAID-4 set, the parity blocks are present on a single drive,
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while a RAID-5 set distributes the parity across the drives in one
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of the available parity distribution methods.
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A RAID-6 set of N drives with a capacity of C MB per drive
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provides the capacity of C * (N - 2) MB, and protects
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against a failure of any two drives. For a given sector
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(row) number, (N - 2) drives contain data sectors, and two
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drives contains two independent redundancy syndromes. Like
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RAID-5, RAID-6 distributes the syndromes across the drives
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in one of the available parity distribution methods.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
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compile this code as a module, choose M here: the module
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will be called raid456.
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If unsure, say Y.
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config MD_MULTIPATH
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tristate "Multipath I/O support"
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depends on BLK_DEV_MD
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help
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MD_MULTIPATH provides a simple multi-path personality for use
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the MD framework. It is not under active development. New
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projects should consider using DM_MULTIPATH which has more
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features and more testing.
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If unsure, say N.
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config MD_FAULTY
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tristate "Faulty test module for MD"
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depends on BLK_DEV_MD
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help
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The "faulty" module allows for a block device that occasionally returns
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read or write errors. It is useful for testing.
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In unsure, say N.
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config MD_CLUSTER
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tristate "Cluster Support for MD (EXPERIMENTAL)"
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depends on BLK_DEV_MD
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depends on DLM
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default n
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---help---
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Clustering support for MD devices. This enables locking and
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synchronization across multiple systems on the cluster, so all
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nodes in the cluster can access the MD devices simultaneously.
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This brings the redundancy (and uptime) of RAID levels across the
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nodes of the cluster.
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If unsure, say N.
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source "drivers/md/bcache/Kconfig"
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config BLK_DEV_DM_BUILTIN
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bool
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config BLK_DEV_DM
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tristate "Device mapper support"
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select BLK_DEV_DM_BUILTIN
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---help---
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Device-mapper is a low level volume manager. It works by allowing
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people to specify mappings for ranges of logical sectors. Various
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mapping types are available, in addition people may write their own
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modules containing custom mappings if they wish.
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Higher level volume managers such as LVM2 use this driver.
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To compile this as a module, choose M here: the module will be
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called dm-mod.
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If unsure, say N.
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config DM_MQ_DEFAULT
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bool "request-based DM: use blk-mq I/O path by default"
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depends on BLK_DEV_DM
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---help---
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This option enables the blk-mq based I/O path for request-based
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DM devices by default. With the option the dm_mod.use_blk_mq
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module/boot option defaults to Y, without it to N, but it can
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still be overriden either way.
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If unsure say N.
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config DM_DEBUG
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bool "Device mapper debugging support"
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depends on BLK_DEV_DM
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---help---
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Enable this for messages that may help debug device-mapper problems.
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If unsure, say N.
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config DM_BUFIO
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tristate
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depends on BLK_DEV_DM
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---help---
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This interface allows you to do buffered I/O on a device and acts
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as a cache, holding recently-read blocks in memory and performing
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delayed writes.
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config DM_DEBUG_BLOCK_STACK_TRACING
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bool "Keep stack trace of persistent data block lock holders"
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depends on STACKTRACE_SUPPORT && DM_BUFIO
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select STACKTRACE
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---help---
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Enable this for messages that may help debug problems with the
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block manager locking used by thin provisioning and caching.
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If unsure, say N.
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config DM_BIO_PRISON
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tristate
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depends on BLK_DEV_DM
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---help---
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Some bio locking schemes used by other device-mapper targets
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including thin provisioning.
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source "drivers/md/persistent-data/Kconfig"
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config DM_CRYPT
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tristate "Crypt target support"
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depends on BLK_DEV_DM
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select CRYPTO
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select CRYPTO_CBC
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---help---
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This device-mapper target allows you to create a device that
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transparently encrypts the data on it. You'll need to activate
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the ciphers you're going to use in the cryptoapi configuration.
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For further information on dm-crypt and userspace tools see:
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<https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
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To compile this code as a module, choose M here: the module will
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be called dm-crypt.
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If unsure, say N.
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config DM_SNAPSHOT
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tristate "Snapshot target"
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depends on BLK_DEV_DM
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select DM_BUFIO
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---help---
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Allow volume managers to take writable snapshots of a device.
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config DM_THIN_PROVISIONING
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tristate "Thin provisioning target"
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depends on BLK_DEV_DM
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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Provides thin provisioning and snapshots that share a data store.
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config DM_CACHE
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tristate "Cache target (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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default n
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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dm-cache attempts to improve performance of a block device by
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moving frequently used data to a smaller, higher performance
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device. Different 'policy' plugins can be used to change the
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algorithms used to select which blocks are promoted, demoted,
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cleaned etc. It supports writeback and writethrough modes.
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config DM_CACHE_SMQ
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tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
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depends on DM_CACHE
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default y
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---help---
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A cache policy that uses a multiqueue ordered by recent hits
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to select which blocks should be promoted and demoted.
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This is meant to be a general purpose policy. It prioritises
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reads over writes. This SMQ policy (vs MQ) offers the promise
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of less memory utilization, improved performance and increased
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adaptability in the face of changing workloads.
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config DM_CACHE_CLEANER
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tristate "Cleaner Cache Policy (EXPERIMENTAL)"
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depends on DM_CACHE
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default y
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---help---
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A simple cache policy that writes back all data to the
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origin. Used when decommissioning a dm-cache.
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config DM_ERA
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tristate "Era target (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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default n
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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dm-era tracks which parts of a block device are written to
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over time. Useful for maintaining cache coherency when using
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vendor snapshots.
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config DM_MIRROR
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tristate "Mirror target"
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depends on BLK_DEV_DM
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---help---
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Allow volume managers to mirror logical volumes, also
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needed for live data migration tools such as 'pvmove'.
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config DM_LOG_USERSPACE
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tristate "Mirror userspace logging"
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depends on DM_MIRROR && NET
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select CONNECTOR
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---help---
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The userspace logging module provides a mechanism for
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relaying the dm-dirty-log API to userspace. Log designs
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which are more suited to userspace implementation (e.g.
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shared storage logs) or experimental logs can be implemented
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by leveraging this framework.
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config DM_RAID
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tristate "RAID 1/4/5/6/10 target"
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depends on BLK_DEV_DM
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select MD_RAID0
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select MD_RAID1
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select MD_RAID10
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select MD_RAID456
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select BLK_DEV_MD
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---help---
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A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
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A RAID-5 set of N drives with a capacity of C MB per drive provides
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the capacity of C * (N - 1) MB, and protects against a failure
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of a single drive. For a given sector (row) number, (N - 1) drives
|
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contain data sectors, and one drive contains the parity protection.
|
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For a RAID-4 set, the parity blocks are present on a single drive,
|
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while a RAID-5 set distributes the parity across the drives in one
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of the available parity distribution methods.
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A RAID-6 set of N drives with a capacity of C MB per drive
|
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provides the capacity of C * (N - 2) MB, and protects
|
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against a failure of any two drives. For a given sector
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(row) number, (N - 2) drives contain data sectors, and two
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drives contains two independent redundancy syndromes. Like
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RAID-5, RAID-6 distributes the syndromes across the drives
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in one of the available parity distribution methods.
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config DM_ZERO
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tristate "Zero target"
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depends on BLK_DEV_DM
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---help---
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A target that discards writes, and returns all zeroes for
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reads. Useful in some recovery situations.
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config DM_MULTIPATH
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tristate "Multipath target"
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depends on BLK_DEV_DM
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# nasty syntax but means make DM_MULTIPATH independent
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# of SCSI_DH if the latter isn't defined but if
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# it is, DM_MULTIPATH must depend on it. We get a build
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# error if SCSI_DH=m and DM_MULTIPATH=y
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depends on !SCSI_DH || SCSI
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---help---
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Allow volume managers to support multipath hardware.
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config DM_MULTIPATH_QL
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tristate "I/O Path Selector based on the number of in-flight I/Os"
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depends on DM_MULTIPATH
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---help---
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This path selector is a dynamic load balancer which selects
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the path with the least number of in-flight I/Os.
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If unsure, say N.
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config DM_MULTIPATH_ST
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tristate "I/O Path Selector based on the service time"
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depends on DM_MULTIPATH
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---help---
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This path selector is a dynamic load balancer which selects
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the path expected to complete the incoming I/O in the shortest
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time.
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If unsure, say N.
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config DM_DELAY
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tristate "I/O delaying target"
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depends on BLK_DEV_DM
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---help---
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A target that delays reads and/or writes and can send
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them to different devices. Useful for testing.
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If unsure, say N.
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config DM_UEVENT
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bool "DM uevents"
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depends on BLK_DEV_DM
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---help---
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Generate udev events for DM events.
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config DM_FLAKEY
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tristate "Flakey target"
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depends on BLK_DEV_DM
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---help---
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A target that intermittently fails I/O for debugging purposes.
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config DM_VERITY
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tristate "Verity target support"
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depends on BLK_DEV_DM
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select CRYPTO
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select CRYPTO_HASH
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select DM_BUFIO
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---help---
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This device-mapper target creates a read-only device that
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transparently validates the data on one underlying device against
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a pre-generated tree of cryptographic checksums stored on a second
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device.
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You'll need to activate the digests you're going to use in the
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cryptoapi configuration.
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To compile this code as a module, choose M here: the module will
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be called dm-verity.
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If unsure, say N.
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config DM_VERITY_FEC
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bool "Verity forward error correction support"
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depends on DM_VERITY
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select REED_SOLOMON
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select REED_SOLOMON_DEC8
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---help---
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Add forward error correction support to dm-verity. This option
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makes it possible to use pre-generated error correction data to
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recover from corrupted blocks.
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If unsure, say N.
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config DM_SWITCH
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tristate "Switch target support (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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---help---
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This device-mapper target creates a device that supports an arbitrary
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mapping of fixed-size regions of I/O across a fixed set of paths.
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The path used for any specific region can be switched dynamically
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by sending the target a message.
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To compile this code as a module, choose M here: the module will
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be called dm-switch.
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If unsure, say N.
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config DM_LOG_WRITES
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tristate "Log writes target support"
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depends on BLK_DEV_DM
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---help---
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|
This device-mapper target takes two devices, one device to use
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|
normally, one to log all write operations done to the first device.
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This is for use by file system developers wishing to verify that
|
|
their fs is writing a consistent file system at all times by allowing
|
|
them to replay the log in a variety of ways and to check the
|
|
contents.
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called dm-log-writes.
|
|
|
|
If unsure, say N.
|
|
|
|
config DM_VERITY_AVB
|
|
tristate "Support AVB specific verity error behavior"
|
|
depends on DM_VERITY
|
|
---help---
|
|
Enables Android Verified Boot platform-specific error
|
|
behavior. In particular, it will modify the vbmeta partition
|
|
specified on the kernel command-line when non-transient error
|
|
occurs (followed by a panic).
|
|
|
|
If unsure, say N.
|
|
|
|
config DM_ANDROID_VERITY
|
|
bool "Android verity target support"
|
|
depends on BLK_DEV_DM=y
|
|
depends on DM_VERITY=y
|
|
depends on X509_CERTIFICATE_PARSER
|
|
depends on SYSTEM_TRUSTED_KEYRING
|
|
depends on CRYPTO_RSA
|
|
depends on KEYS
|
|
depends on ASYMMETRIC_KEY_TYPE
|
|
depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
|
|
---help---
|
|
This device-mapper target is virtually a VERITY target. This
|
|
target is setup by reading the metadata contents piggybacked
|
|
to the actual data blocks in the block device. The signature
|
|
of the metadata contents are verified against the key included
|
|
in the system keyring. Upon success, the underlying verity
|
|
target is setup.
|
|
|
|
config DM_ANDROID_VERITY_AT_MOST_ONCE_DEFAULT_ENABLED
|
|
bool "Verity will validate blocks at most once"
|
|
depends on DM_VERITY
|
|
---help---
|
|
Default enables at_most_once option for dm-verity
|
|
|
|
Verify data blocks only the first time they are read from the
|
|
data device, rather than every time. This reduces the overhead
|
|
of dm-verity so that it can be used on systems that are memory
|
|
and/or CPU constrained. However, it provides a reduced level
|
|
of security because only offline tampering of the data device's
|
|
content will be detected, not online tampering.
|
|
|
|
Hash blocks are still verified each time they are read from the
|
|
hash device, since verification of hash blocks is less performance
|
|
critical than data blocks, and a hash block will not be verified
|
|
any more after all the data blocks it covers have been verified anyway.
|
|
|
|
If unsure, say N.
|
|
|
|
config DM_BOW
|
|
tristate "Backup block device"
|
|
depends on BLK_DEV_DM
|
|
select DM_BUFIO
|
|
---help---
|
|
This device-mapper target takes a device and keeps a log of all
|
|
changes using free blocks identified by issuing a trim command.
|
|
This can then be restored by running a command line utility,
|
|
or committed by simply replacing the target.
|
|
|
|
If unsure, say N.
|
|
|
|
endif # MD
|